Decision making, evidence, audit, and education: case study of antibiotic prescribing in general practice.

OBJECTIVES: To describe a group general practice's implementation of a decision to prescribe 3 day courses of 200 mg trimethoprim twice daily for urinary tract infections in women and to compare 3 day courses with 5 and 7 day courses. DESIGN: Record review, audit of trimethoprim prescribing for urinary tract infections, and critical appraisal of evidence originally presented in support of 3 day course. SETTING: Group general practice in Newcastle upon Tyne. DATA SOURCES: The records of all female patients aged 12 years and older who were prescribed trimethoprim for uncomplicated urinary tract infections during a 12 month period were reviewed. 271 valid records were identified. DATA EXTRACTION: Prescribing rates for different courses of trimethoprim, rates of patients returning for second consultations, rates of urine cultures, results of cultures, results of critical appraisal of evidence. RESULTS: 114 of 271 (42%) prescriptions written at the first visit were for 3 day courses. 16 of 114 (14%) patients who had had a 3 day course of treatment returned for a second consultation compared with 6/83 (7.2%) of those who had had a 5 day course and 8/74 (11%) who had had a 7 day course. The difference between 3 day and 5 day courses in rates of returning for second consultations was 6.8% (95% CI -1.7% to 12.6%) and between 3 day and 7 day courses was 3.2% (-3.6% to 10.0%). Appraisal of the original evidence on which the practice based its recommendations showed that it was flawed. Additional evidence was found in the Cochrane Library. CONCLUSIONS: Our original decision, made by consensus at a meeting of the practice's partners, had not led to a consistent change in practice. We did not find a significant increase in treatment failures among patients treated with the 3 day regimen.